1. Technical Field
The invention relates in general to digital image processing, and in particular to a system for minimizing the visual effect of local pixel defects.
2. Related Art
Pixel defects are a well-known problem in digital photography. A typical digital imager has an array of hundreds of thousands to millions of photocells (i.e., pixels) that produce electrical responses to light exposure. Ideally, each pixel should produce the same electrical response for a given quantity (i.e., intensity and the duration) of light exposure. Usually, however, at least a few of those pixels will be defective. Some isolated photo cells or pixels may produce too much, too little, or even no electrical response at all. As a result, a captured image may have bright or dark point defects.
One method for minimizing pixel defects in an image is to transform the image from the spatial domain to the spatial frequency domain, apply various filters to remove the high frequency components which tend to be associated with point defects, and then convert the image back to the spatial domain. This method of eliminating pixel defects utilizes a great deal of processing power, without utilizing the real-time, cost-effective Fourier-transforming capability of a simple optical device.